I would like to ask whether it is possible.
The model and type replacement on TV.
Thus, more features are available.
(I hope I'm not meaningless to my question.)
Tanks for help!
I certainly managed to do it on my LE40C530 which doesn't have a LAN network connection. By changing it to a C550 in de Service Menu and adding a WIFI stick in the USB port it now does have the network connection (although through WLAN). Works fine.
I can't remember exactly how, but in my case there were a few more steps needed which involved the Hotel Menu and the USB port to gain access and get the WIFI stick to work.
Changing the model in the Service Menu : Enter 'Option' by pressing right arrow button. Move down (down-Arrow) to 'Model' enter the selection by hitting right-arrow. With the left- and right arrow buttons you can change the model. IMPORTANT: Use the 'RETURN' button to leave any submenu.
Obviously you cannot just select any (higher-spec) model and expect it to work. The hardware needs to present. Like I did, I would recommend to search this forum and/or the web for models close to yours, so with the same hardware and check if somebody has got it working already.
In general be very careful when navigating through the Service Menu as it is very easy to accidentally change any settings and (when worse comes to worse) ruin your tv . As said before entering a submenu in de Service Menu you do by pressing the right arrow button, but to go back up again you need to hit the RETURN button. Pressing the left or right button in a submenu may change the setting (potentially without you being aware you did so). So this could be tricky. You may want to take photographs from every page for later reference if you're not comfortable with it.
Please note I am just a (careful) layman who got it working after lot of research and learning from the people who really know what they are doing....